Hi, I have been using Darktable for quite a while without any problems processing raw photos of my Nikon Z6II. Recently I upgraded to a Nikon Z8 using the raw lossless settings. However developing lossless raws is quite painful, since 1 in 5 photos is displayed pitch black in lighttable or darkroom. Sometimes I was able to find a filter like denoise, that when turned off, led to the photo beeing displayed as is but not completely black. For other photos I was unable to find a filter that caused the black view. Sometimes when restarting darktable this leads for a previously black photo to be displayed normally again. I was unable to find a rule when or why a photo is shown pitch black and when not.
Is there a remedy for this problem, which works better than trying to turn off all used filters?
Thanks Rainer
I had a similar issue with a few images lately as well.
It appeared I had two versions installed, and had switch by accident to the older version…
Once I went back to the newest installed version, I could correct the issues (of course, I then removed the older version 
).
Ok, I see. Well, I first tried 5.2 and later 5.4 (currently the latest version). Both show this strange effect.
Try resetting the raw black/white level module or/and clearing the history.
Thanks for the history & B/W balance tips. Resetting the history worked fine. Now I am able to process this raw. I also converted the .nef file to dng which also worked fine for ASP, but since I use linux this would be a cumbersome way since there is no tool for linux to do the conversion to dng. This one time I used a web tool that did the job.
Thanks
Rainer
Do mean the high efficiency raw setting? Those will not work in darktable.
Or just the regular Nikon raw nef files?
Since I switched to that setting I have not had any issue.
Possibly you can you dnglab to convert the nef file to the dng format